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<title>菜鸟教程(runoob.com)</title>
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<h1>使用 "use strict":</h1>
<h3>不允许删除变量或对象。</h3>
<p>浏览器按下 F12 开启调试模式，查看报错信息。</p>
<script>
"use strict";
var oo=void(0);
var x = 3.14;
// delete x;   
var y={x:1,z:8} ;
"use strict";
delete y.x;
console.log(y);
</script>

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